The present invention is directed to a process for the recovery of erythorbate values from spent photographic solutions.
Typically, the processing of silver halide emulsions begins with the exposure of the emulsion to radiation to which the emulsion is sensitized to produce a latent image in the silver halide grains of the emulsion. The latent image is developed by immersion of the exposed emulsion in an aqueous developing solution usually containing a reducing agent which functions as a developer. An example of such a reducing agent is hydroquimone.
Other developing agents which have been used are derivatives of ascorbic acid, i.e. erythorbic acid or erythorbates. The use of these derivatives as developers are discussed in a number of United States Patents.
U.S. Pat. No. 3,942,985 refers to a developer composition comprised of at least one iron chelate developer and ascorbic acid, or specific derivatives thereof.
U.S. Pat. No. 2,688,549 refers to a photographic composition which uses ascorbic acid, and specified derivatives thereof, together with 3-pyrazolidone compounds as a developing medium.
U.S. Pat. No. 3,022,168 refers to photographic developer compositions which use ascorbic acid as a developer. The compositions are at a pH of from about 8.5 to about 9.
U.S. Pat. No. 5,098,819 refers to a photographic composition containing ascorbic acid; specified derivatives thereof, a sulfite, an alkali metal carbonate and a 3 pyrazolidone compound. The composition is at a pH of from 9.75 to 10.6.